Back in the day, tables were the only option. At this point, nearly all scuba divers wear a dive computer and for good reason.
The computer tracks your depth, time, speed of ascent, and NDL in the moment. Tables give you a static plan. When you move between depths partway through, it updates. Tables are set before you get in.
Watch-style computers are what most people buy at this point. These are small enough, readable underwater, and you'll wear them as a regular watch as well. Console-mount computers are an option but fewer buyers read choose them these days.
Budget computers run about $300-odd and do everything the average diver needs. Features include depth tracking, time, NDL, a logbook, and usually a basic freedive function. Stepping up to mid-range gets you wireless air monitoring, better readability, and more mix modes.
The one thing buyers overlook is algorithm differences. Some algorithms are more conservative than others. A cautious setting gives you shorter no-deco time. Liberal ones give more time but at reduced buffer. Neither is wrong. It's what you're comfortable with and your diving background.
Ask the staff at a local dive store who dives with various brands before buying. Good dive stores will have real-world feedback on which ones hold up and what isn't hype. The better Cairns dive stores publish gear reviews and comparisons on their sites too